If you want ease of use and an OS that does everything, Win7 is the winner, sadly enough.

If you have a netbook, preferably an ASUS due to availability of open source drivers, then MeeGo is unbeatable, even better than win7. Ubuntu NR has much more ready apps, but MeeGo is generally faster and much more enjoyable.

For a laptop or desktop, Ubuntu is by far the best *nix all things considered. OpenSuse is a good second, but much more cumbersome.

But my favorite OS is puppy linux. It is easy to use when getting used to it and it is a must when you are trying different OS'es and you are constantly repartitioning your hard-drive. It can be installed in no space at all, and after a while you will use it more and more